THE INFLUENCE OF PARAMETERS ON THE HARDNESS OF WC-12Co ALLOY COATING ON GX 15-32 GREY CAST IRON SUBSTRATE BY HVOF SPRAYING TECHNOLOGY

Abstract

In the field of mechanical processing, high-velocity Oxy-Fuel (HVOF) thermal spraying technique is commonly used to repair and increase the service life of parts that are worn due to contact such as lathe tool carriages. This study aims to evaluate and analyze the impact of HVOF technical parameters on the hardness of WC-12Co alloy coatings applied to GX 15-32 gray cast iron. Three main factors were studied and investigated: Spray distance (L), powder supply amount (m) and finally spray velocity (V). The Vickers hardness (HV) test results indicate that spray distance and particle velocity have a significant impact on the coating properties. Under the optimal spray distance and high spray velocity conditions, the coating achieves the highest hardness, while minimizing porosity and improving adhesion. On the contrary, if the parameters are not set correctly, the coating is prone to defects such as cracking or peeling. The research results are very important for optimizing the HVOF coating process, thereby applying it to the restoration of lathe tool tables, improving durability and service life, helping to reduce maintenance and repair costs and improve machining efficiency.